Back behind the wheel: Summer sun…and UV rays

July 1, 2005

Now that summer is here, it is the season to be active and enjoy the outdoors. It has been a while, but winter and spring are finally over. Hopefully this summer you will have the opportunity to enjoy...

July 1, 2005
by
Dr. Jerry Singh

Categories

Now that summer is here, it is the season to be active and enjoy the outdoors. It has been a while, but winter and spring are finally over. Hopefully this summer you will have the opportunity to enjoy the weather.

But be careful, too much sun can increase your risk of skin cancer, and can cause permanent damage to your eyes.

The sun provides energy that sustains all life on earth. However, some of the energy that is emitted from the sun (ultraviolet rays) can also be harmful. Ultraviolet (UV) rays are just one form of light energy that the sun emits.

UV rays are invisible to the human eye. There are three types of UV light, UV-A, UV-B, and UV-C. UV-A is the “weakest” form of UV light energy. Prolonged exposure to UV-A will cause your skin to age quicker (wrinkles) and cause your patio furniture to fade.

But UV-B is even stronger than UV-A and is more detrimental to your health. This wavelength of light is responsible for causing skin cancer, macular degeneration and cataracts.

And UV-C is even stronger still than UV-B, though it is of little concern. The ozone layer (atmosphere) acts as a filtre, and prevents UV-C rays from reaching the earth’s surface.

The ozone layer is located 15-40 kms above the earth’s surface. It is composed of ozone, which is a gas that is composed of three atoms of oxygen.

The ozone layer is very important because it filters out (absorbs) most of the UV-B and all of the UV-C rays. If there is a depletion of this layer, subsequently more UV-B rays will be reaching the earth’s surface. Maintaining the ozone layer is very important in order to limit our exposure to UV-B rays.

The amount of UV that you are exposed to depends on many factors. Seasons (summer vs. winter), the geographical location (equator vs. the north pole), time of day (midday greatest UV), the amount of cloud cover, the type of surface that you are on (water/snow vs. concrete/sand), the elevation (higher = more UV) you are at, the clothes that you wear and the amount of time you are in the sun will all determine the amount of your UV you are getting.

In 1992 Canadian scientists developed a method to predict the strength of the sun’s UV rays, based on the day to day changes in the ozone layer.

Also in the same year, the UV index was developed. Canada was the first country in the world to issue nation wide daily forecasts of the predicted UV for the next day. This UV index is very important for obvious reasons. UV is measured on a scale, which ranges from 0 to 10 in Canada.

The higher the UV index, the more UV is reaching the earth’s surface, the less time you should be in the sun.

If you are in the sun for too long and too often, the UV rays will slow down this regeneration process. As a result, you get more wrinkles and increase your risk for skin cancer. UV rays can also affect your eyes, which can cause cataracts and macular degeneration.

To protect yourself from the harmful rays, you can stay out of the sun or apply suntan lotion. As a general rule, you should always use a suntan lotion that has a minimum SPF (Sun Protection Factor) of 15. Depending on your skin type, it will determine what SPF you should be using. The lighter your skin is, the higher (more protection) the SPF should be. The darker your skin is, the lower SPF factor you can use. You should also have a good pair of sunglasses that have UV protection or are polarized to help protect your eyes while driving. Remember it does not have to be hot outside for the UV rays to cause damage. This is important when driving on those bright and sunny winter days.

There are three types of skin cancer that can occur as a result of overexposure to UV rays.

That is next month’s topic.

Until then take care, drive safely and don’t forget to put on your suntan lotion (for that arm hanging out the window) and sunglasses!